PSP wont power up or turn on no green light

PSP History : 1.50 to 3.52 m33 to 3.71 m33 upgraded successfully i decided to update my PSP firmware to 3.80 m33 before upgrading reformat my memory stick first and noticed that my psp is not detecting the right size of my ms stick it says not enough space to copy the update space available is 30.mb only considering Im using a 4gb mstick. I turned it off and decided to go to recovery console by pressing R and switching on the psp even just turning on the power switch only.

But it wont turn on no green light no anything! I tried my brothers psp battery but same thing nothing happen. I tried my battery to his and it work fine.

Can you give me advice on how to fix this? I need your help very badly pls. help me. My son is the one who always plays with it. Pls help.